Nebulae and How to Observe Them

Lyra Nebulae
M 57 PLNNB LYR 18 53.6 +33 02
The Ring Nebula is probably the most famous planetary nebula in the sky. Using
the 4 inch and a 27mm Panoptic eyepiece it is easily seen as a nonstellar dot. Even
though it is tiny, there is an elongated dot in a pretty rich field of view. Raising
power with the 8.8mm makes this an obvious ring. The annular disk is elongated
1.8X1 with a dark center that is more obvious with averted vision.
The Nexstar 11 at high power will reveal a thin fog of material that fills the Ring.
John Herschel said this appeared to him like “gauze over a hoop” and I agree. With
a 6.7mm eyepiece the effect is obvious. The central star is never seen as a steady
dot of light in the middle of the Ring, but it does wink at me occasionally. I would
estimate that I see the central star 5 percent of the time.Adding the OIII filter really
enhances the annular glow of the Ring, but the central star is no longer seen with
the filter in place.
Over 20 years ago the Saguaro Astronomy Club helped the staff at Kitt Peak
Observatory pass legislation in Arizona that limited outdoor lighting. As a reward
for our help we were provided two hours of observing time on a 36 inch f/7.5 telescope.
A more eager group of observers never existed, including the student telescope
operator; he had never had a chance to just observe with the telescope. We
realized that the field of view would be small, so we chose objects to observe that
would fit, and the Ring was first on the list. The old 25mm Kellner eyepiece that
was used every night to get the photometer aligned on target was a mess, but even
then we knew it was going to be a great view. We replaced the old eyepiece with
my brand-new 16mm research grade Erfle. That put the scope at 427X and the Ring
Nebula was at its best. The annular structure was a medium green color and the
central star was held steady about 40 percent of the time. The nebulosity within
the ring shape was easy and really became enhanced with averted vision. In
moments of good seeing there were thin fingers of nebulosity that pointed inward
toward the central star. The ring shape is about one third of the field of view in
this telescope. We called it the “Giant Green Donut.” It was a memorable night if
ever there was one.
This image of the Ring
Nebula is by Chris Schur
with a 12.5 inch f/5
Newtonian.
Northern
Summer Nebulae
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